Safety device for lift and hoist cages



Dec. 6, 1949 R BARTON ET AL 2,490,613

SAFETY DEVICE FOR LIFT AND HOIST CAGES Filed July 12, 1947 2 Sheets-Sheet l Raw Barton and PW Adlai Ill? Aiiornny.

Dec. 6, 1949 R. BARTON ETAL 2,490,613 SAFETY DEVICE FOR LIFT AND HOIST CAGES Filed July 12, 1947 2 Sheets- Sheet 2 Invx vtars,

Raw BarIa'n m Plzilih Adler fur dmm Sim Patented Dec. 6, i949 SAFETY DEVICE FORTIFT HOIST CAGES Ralp'hBarton, Deane, Bolton, and Philip Adler, Salford, England Application July 12, 1947; Serial No. 160:1520 In Great Britain May 28, 1946 Section 1, Public Law 690,:Au'gust8QI946 6 Claims. 1

"This invention relates to that kind of safety device for lift or hoist cages and the like, which, ron breakage of the hoisting cable or rope acts son the guide rod or ropes to suspend the cage or the like thereon, and thereby prevent the cage or the like from falling.

.Asafety device of the hereinbefore specified ikirrdiior lift and hoist cages and the like inactcordance with our invention has frictional clamp- .cing means slidably but non-rotatably mounted on thielguide 'ropes or rodsand operated by screw :me'ans first actuated automatically by an arm on its release by breakage-of the hoisting cable urrope so as to cause the clamping 'devicesrloosely :to :grip the guide ropes or rods sufficiently to retard the downward sliding of the clamping devices on the guide ropes or rods and thereupon further automatically actuated by means connected to the cage or the like on therdescent of the cage away from the vclamping devices so as to relatively gradually cause the clamping devices to increase their grip on the guide ropes or rods sufficiently to prevent further vdownward slip- :ping of the clamping means and thereby hold the cageior the like in suspension by the gripping devices acting through the said connections.

"The screw means may comprise a spindle having screw-threads of opposite hand at its ends which screw into two :clamping devices and provided with the said lever and also with-arms connected to the cage or the like by chains or other flexible or pliable connecting'members.

The arm may be adjustably mounted on the said spindle.

Each clamping device may consist of a block having a fixed clamping surface and a movable clamping member adapted to be forced towards the fixed clamping surface by the action of the respective screw-thread of the spindle.

In the accompanying drawings which are more or less diagrammatic- Figure 1 is a fragmentary frontelevation partly in section, of a safety device for lift and hoist cages and the like.

Figure 2 is a plan view thereof, partly in section.

Figure 3 is a side view thereof, the left hand side of the figure being in section taken on line 3-3 of Figure 1 and the right handside a section taken on line 4-4 of Figure 1.

Figure 4 is a side view'in section taken on a line corresponding with line 3-3 of Figure 1, and showing the part in a different position.

Referring to the drawings; in the construction" shown therein as applied by way of example 'to a colliery cage suspended from a hoisting cable by connecting means i, such as chains, which extend from its upper corners to a connecting member 2 on the endof the hoisting cable and guided by four guideeables 3 arranged near its vertical corners and engaging guide *blocks l secured to the-cage, we provide-on each guide-cable 2 a slida'bleblock Shaving a fixed ver- -tic'a'l clamping face- '6 anda vertical but horizontally 'slidable jaw -1 carrying 'a clamping face -8, the 'guide-caIdIe dbeing between "the two clamp- -ing faces '5 a-nd-8 which are grooved to guide the cable; Each two guide blocks 5 which face each-other across "the topoi the cage can rest *on the g-uide blok 4 beneath it whilst the cage is ascendingand therefore be caused to slide up the cables 3 as the cage is "hoisted. The opposed faces of the two blocks 5 have screw-threaded, horizontal holes; the screw-thread of the hole in one of the-blocks 5 being a right-hand one and the screw-thread in the "other block 5 being a l e f't han'd one. The two holes are in alignment and lead :to the slidahle jaws "l. The screwthreads are multiple and have a quick pitch.

A spindle! is arranged to extend across the cage and its *ends' have screw-threads of opposite hand and are screwed into the screwthreaded h'oles in theblocks 5, so that the blocks 5 are connected to the spindle 9 and the spindle ll by rotation can be screwed further into the blocks 5; The blocks 5 are'the only means of support of-the :sp'in'dle 9.- The spindle 9 has on an adjustable arm 10' which has a weight H which strives to pull the arm downwards. Instead of the-weight, 'or-in addition thereto, a :spring may be-providedto serve the same purpose. When-the hoisting rope carries the cage, the striving is defeated by'the engagement of the-end of the s'aid arm l dwitha -l 2 hanging from the connecting member 2 The arm l d is rendered-adjustable in one direction without rotation at the spindle, by mounting -it loosely on the spindle 9 and securing to the spindle'aratc'het wheel 1 3 which, by co-operation with a pawl M on the arm Hi; causesthe arm mm rotate the spindle 9"when it falls.

spindle 9 hastwo levers --l=4, 1-5 secured to it; The arm-l-4-of each lever has a hook -like catch #8 which engages a hole-I 6 in "a cross-memher ll provided at the-top of the cage-and thereby causes through the spindle 9 the blocks 5, to slide -downwards when the cage is lowered and prevents the cage from moving vertically away frornthe spindle V firearm-l5 of each lever is connected by a chain 19 to the corresponding cross-member H. The chain 19 is of sufficient length as to have considerable slack.

In operation, when the hoisting cable is intact, the ends of the spindles 9 do not press the slidable jaws 1 against the guide cables 3 and the blocks are therefore able to slide freely along the guide cables 3 as the cage is hoisted or lowered, the cage acting to push them before it as it rises and to draw them after it as it descends.

On breakage of the hoisting cable the connecting members I fall on to the top of the cage and thereby allow the arms ill to swing downwards under the action of the weights ll and/or springs until they are stopped by the top of the cage or a forked stop thereon (not shown) and thereby to rotate the spindles 9 a predetermined amount in the blocks 5 which are held against rotation by the guide ropes 3, and also the swing catches IS on the arms hi clear of the apertures l6 and thereby unhook the catches from the cross-members H. The release of the arms [4 from the cross-members ll leaves the falling cage free to increase its distance from the blocks 5 and the said distance is caused to increase because the limited initial rotation of the spindle 9 forces the slidable jaws 1 against the guide cables 3 and causes them to be gripped between the clamping faces 6 and 8. The gripping action is relatively slow and proceeds initially only up to a stage where the blocks 5 still remain free to slide downwards on the guide cables 3, but at a reduced speed, due to the friction created by slidable clamping faces 8 being forced by the spindle 9 a predetermined amount towards the fixed clamping faces *6. As the cage continues to fall away from the spindle 9, the spindle 9 is left free to rotate further and thereby increase the clamping and therefore breaking action of the clamping faces 6 and 8 relatively gradually and thereby further slow the fall of the blocks 5. As the distance between the cage and the spindle 9 and therefore the blocks 5 increases, the chains l9 connecting the arms is to the cage lose their slackness and also act through the arms IE to assist the continued rotation of the spindle 9 until by the time the chains have become taut the spindle 9 has caused the guide cables 3 to be gripped so tightly by the clamping faces 6 and 8 that the blocks 5 become immovable thereon, at which point the cage, because it is now suspended from the guide cables 3 through the blocks 5, spindles 9, arms 15, chains 19 and cross-members I1 is prevented from falling further. The parts are then in position shown in Figure 4.

The action of the safety device is sumciently gradual as to transfer the inertia of the descending cage to the guide cables 3, in a successive manner and so gradually that the guide cables 3, or rods if rods are used instead of guide cables, are not broken or collapsed by the weight of the descending cage.

We claim:

1. A safety device for lift and hoist cages and the like, comprising guide members for guiding the cage, a hoisting cable connected directly to the cage, two frictional clamping blocks normally resting on the cage and slidably but non-rotatably engaging the said cable, a fixed clamping jaw forming part of each block, a movable clamping jaw forming another part of each block, a rotary screw-threaded spindle connecting the clamping blocks together and screwing in the blocks for forcing the jaws into frictional contact with the guide members, an arm fixed on the spindle for rotating the same and thereby making the clamping blocks grip the guide members lightly when the arm is permitted to operate, means on the hoisting cable for preventing operation of the arm until the hoisting cable breaks, further arms on the spindle for rotating the same, and normally loose chains connecting the further arms to the cage for firstly causing further rotation of the spindle when the blocks grip the guide members lightly and thereby making the clamping bloc-ks progressively grip the guide members more tightly until the blocks can no longer slide on the guide members and secondly for suspending the cage from the spindle when the blocks have become fixed on the guide member and thereby suspending the cage by the guide members.

2. A safety device for lift and hoist cages and the like, comprising guide members for guiding the cage, a hoisting rope for hoisting the cage, clamping devices engaging the guide members above the cage, loose chains connected to the top of the cage, arms connected to the cage by the loose chains, a rotatable spindle to which the arms are fixed, hooks on the spindle, means on the cage disengageably engaged by the hooks, right and left hand screw-threads on the spindle engaging and operating the clamping devices, a further arm provided on the spindle, means for angular adjustment of the said further arm on the spindle, and means connected to the hoisting cable for holding the said further arm inoperative while the hoisting cable is unbroken.

3. A safety device for lift and hoist cages and the like comprising guide members for guiding the cage, a clamping device engaging each guide member, a fixed clamping surface and a movable clamping member on each guide device with the guide member lying between the fixed surface and the movable clamping member, a screw-threaded hole in each clamping device, a rotatable spindle having right and left hand screw-threads engaging the holes of two of the said clamping devices, arms on the spindle, slack chains connecting the arms and therefore the spindle and the two clamping devices permanently to the cage, hooks on the spindle connecting it and thereforev the two clamping devices to the cage until the spindle is rotated, a further arm, a hoisting cable, chains directly suspending the cage from the hoisting cable and a link hanging loosely from the hoisting cable and having the end of the said further arm resting loosely in it in an inoperative position. i

4. A safety device for lift and hoist cages an the like, comprising guide members for guiding a cage, a two-part, untightened frictional clamp mounted on each guide member, catch means disconnectably attaching the clamps to the cage, means for releasing the catch means and thereby freeing the cage from its attachment to the clamps by the catch means and also tightening the clamps on the guide members, and slack means connecting the clamps to the cage for tightening the clamps after the cage has fallen away from the clamps and thereafter suspending the cage from the clamps.

5. A safety device for lift and hoist cages and the like, comprising in combination four guide members for guiding a cage, a two-part, untightened frictional clamp mounted on each of the four guide members, a rotary spindle connectin two of the clamps together, a second rotary spindle connecting the remaining two clamps together, screw-threads on the ends of the spindles for closing the clamps on the guide members, holes provided on the cage, catch arms fixed to the spindles, catch hooks on the arms engaging the holes for disconnectable attachment of the clamps to the cage, a constantly loaded operating arm rotatively provided on each spindle for rotating the spindle and thereby disengaging the catch hooks from the said holes and simultaneously initially closing the clamps with an initial brakin grip on the guide members corresponding to the constant load on the arms, operating and connecting arms on each spindle, draft members connected at one end to the said operating and connecting arms and at the other end to the cage and forming a slack connection between them for further closing the clamps by the weight of the cage with an increased grip by further rotating the spindles and for holding the cage suspended from the spindle and therefore from the clamps after the cage has fallen away from the clamps during an interval in which the rate of fall of the clamps has been reduced by the initial brakin grip.

6. A safety device for lift and hoist cages and the like, comprising in combination four guide members for guiding the cage, a two-part untightened clamp slidably mounted on each guide member, catch means disconnectably attaching the clamps to the cage, means for operating the catch means and thereby freeing the cage from connection by the catch means, rotary spindles for operating the catch means and tighteningthe clamps, a ratchet wheel fixed on each spindle for rotating it, a weighted arm rotatably mounted on the spindle, a pawl mounted on the weighted arm and engaging the ratchet wheel for rotation of the ratchet wheel in operative direction by the weighted arm acting through the pawl, slack means connecting the clamps to the cage for delayed suspension of the cage from the clamps after the cage has been freed from connection by the catch means, hoisting means directly connected to the cage and hanging members on the hoisting means for loosely supporting the ends of the said arms.

RALPH BARTON.

PHILIP ADLER.

REFERENCES CITED The following references are of record in the file of this patent:

Number 

